The present invention relates to overhung boring bars for accurately machining bores and in particular bores of non-uniform diameter along their length, for example stepped and tapered bores.
Problems arise in machining long bores since as the length of the boring bar is increased (for a given cross-section) the boring bar becomes increasingly prone to the build-up of chatter.
Thus conventional boring bars with diameters in the range 25 mm. to 40 mm. become unsatisfactory in this respect when their overhung ratio (i.e. ratio of the free length of the boring bar to its diameter) exceeds 5:1.